JP3292121B2 - AGC amplifier control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AGC (Auto Gain
The present invention relates to an amplifier control circuit, and more particularly, to an AGC amplifier control circuit that performs level adjustment together with a step attenuator in a transmitter or a receiver.

[0002]

2. Description of the Related Art Conventionally, an AGC amplifier control circuit is used, for example, in a transceiver, for adjusting transmission or reception power together with a step attenuator arranged near an antenna.

FIG. 4 is a block diagram showing an example of an AGC amplifier control circuit of the first conventional example. In FIG. 4, a transmission attenuator TX ATT21 and a reception attenuator RX
ATT10 passes RF signal as it is (OFF state)
Or attenuate (ON state) by a certain amount,
Step attenuator having a selective function as described above.

[0004] TX ATT controller 40, RX ATT
The control device 30 includes the TX ATT 21 and the RX A
Control is performed so that the attenuation characteristic of the TT 10 becomes a hysteresis characteristic with respect to the transmission or reception level at the antenna end. The transmission AGC amplifier TXAGC24 and the reception AGC amplifier RX AGC13 adjust the gain of the transmission or reception IF signal power. TX storage circuit 27, RX storage circuit 1
Reference numeral 6 stores the control voltage data of the transmission or reception AGC amplifier corresponding to the transmission or reception level for each ON / OFF state of the transmission or reception attenuator. Transmit or receive digital-to-analog converter TX
D / A 26 and RX D / A 15 transmit or receive AG
The digital value of the control voltage of the C amplifier is converted into an analog voltage and output, and the gain of the TX AGC 24 and the RX AGC 13 is controlled.

If the control voltage Vcnt vs. gain characteristic of the AGC amplifier used is not linear as shown in FIG. 5, the gain of the AGC amplifier does not match the desired transmission level at the antenna end or the reception level at the antenna end. Are controlled to change linearly as shown in FIGS. For this purpose, transmission level versus transmission control voltage Vtx characteristics as shown in FIG.
Also, a reception level versus reception control voltage Vrx characteristic as shown in FIG. 8 is required. In the TX storage circuit 16 and the RX storage circuit 27, control voltage data having the relationship shown in FIG. 6 and FIG. 8 is stored, and when data indicating a transmission or reception level is input as an address, the specified transmission or reception The reception control voltage data is output. Here, the unit of the transmission level and the reception level, and the unit of the gain of the transmission and reception AGC amplifier is [dB].

Next, the operation will be described. In the description of the operation of the conventional example, the respective explanatory diagrams of the data conversion of the transmitter and the data conversion of the receiver of FIGS. 2 and 3 corresponding to the description of the operation of the present invention will be used.

First, the transmitter will be described. TX AT
The T control device 40 controls the TX ATT 21 in a hysteretic manner with respect to the transmission level as shown in FIG. The control based on the hysteresis is that the transmission level is TX ATT.
This is to prevent the ON / OFF switching from occurring continuously, that is, to prevent chattering when the user has settled near the level at which the ON / OFF switch 21 is performed. When the transmission level is low, the TX ATT 21 is turned on to attenuate to improve NF. In the same figure, when the TX ATT 21 is in the OFF state and the transmission level becomes lower than the point A, the TX ATT 21 becomes O
When the transmission level becomes higher than the point B in this state instead of the N state, the TX ATT 21 is turned off again, and the RF signal passes without being attenuated.

At points A and B at which the TX ATT 21 switches ON / OFF, the TX AGC 24 changes the gain in the opposite direction by the same amount as the attenuation of the TX ATT 21 so that the transmission level at the antenna end does not change discontinuously. I have to do it. FIG. 2B shows the relationship between the transmission level and the gain of the TX AGC 24. TX
The AGC 24 determines the TX ATT 21 for the transmission level.
Has a gain corresponding to each of the ON / OFF states, and where the transmission level is between point A and point B, there are two types of gain. Therefore, the TX storage circuit 2
7 is where the transmission level is between points A and B,
The control voltage data for the ON / OFF state of the TX ATT 21 is stored.

Next, the receiver will be described. RX AT
The T control circuit 18 converts the RX ATT 10 into (a) in FIG.
Is controlled in a hysteresis manner with respect to the reception level as shown in FIG.
If the reception level is high, the RX ATT 10 is turned on to attenuate the signal to prevent IM (intermodulation), and if the reception level is low, the RF signal is passed without being attenuated. In the same figure, RX ATT10
Is in the OFF state and the RX ATT10 turns ON when the reception level becomes higher than the point B. When the reception level becomes lower than the point A from this state, the RX ATT 10 is turned off again, and the RF signal passes without being attenuated.

At points A and B where the RX ATT 10 switches ON / OFF, the RX AGC 13 increases the gain in the opposite direction by the same amount as the attenuation of the RX ATT 10 so that the input level of the demodulator DEM 14 does not change discontinuously. I have to change. FIG. 3B shows the relationship between the reception level and the gain of the RX AGC 13. The unit of the reception level and the gain of the RX AGC 13 is [d
B], and generates control voltage data such that the slope becomes “−1” in order to keep the input level of the demodulator DEM14 constant.

The RX AGC 13 has a gain corresponding to the ON / OFF state of the RX ATT 10 with respect to the reception level, and has two kinds of gains when the reception level is between the points A and B. become. Therefore, the RX storage circuit 16 controls the ON / OFF of the RX ATT 10 when the reception level is between the points A and B.
The control voltage data for each state is stored.

Japanese Patent Application Laid-Open No. Sho 60-227574 discloses a conventional "amplifying amplifier for television" disclosed in Japanese Patent Application Laid-Open No. Sho 60-227574. Displays whether the function is working or not.

The "attenuator circuit" disclosed in Japanese Unexamined Utility Model Publication No. 7-33024 of the prior art 3 is capable of performing variable and distortion-free control in 1 dB steps in a high-frequency attenuator having a large attenuation.

[0014]

However, the first problem in each of the above prior arts is that the amount of data stored in the storage circuit increases. The reason is that the gain control voltage data of the AGC amplifier with respect to the transmission or reception level must be stored for each ON / OFF state of the attenuator.

A second problem is that the number of bits of an address for specifying data stored in the storage circuit increases, and the address specifying process becomes complicated. The reason is that the address configuration needs to add not only the transmission or reception level but also information indicating the ON / OFF state of the attenuator.

An object of the present invention is to provide an AGC amplifier control circuit capable of reducing the amount of data stored in a storage circuit and simplifying an address for designating stored data.

[0017]

In order to achieve the above object, an AGC amplifier control circuit according to the present invention comprises: an RF attenuator (ATT) for controlling a gain of an RF signal in a stepwise manner;
An AGC amplifier for continuously controlling the gain of the RF signal,
A storage circuit for storing data for linearly controlling the gain control of the AGC amplifier, and a data converter for outputting control data for obtaining a gain for compensating the stepwise attenuation of the RF attenuator with the AGC amplifier to the storage circuit. with circuit and, the ATT control circuit for controlling the operation of RF attenuator and the data converting circuit receives the predetermined reception level control signal, a
Storage circuit for associating GC amplifier gain with desired output
Is stored, the RF attenuator is activated and the specified attenuation is
The AGC amplifier gain corresponding to this amount of attenuation.
Data conversion circuit to increase the
The reception level to the address of the storage circuit
Use the value after data conversion considering the data attenuation
Thereby, the amount of data stored in the storage circuit can be reduced,
It is characterized in that the data amount can be reduced .

The AGC amplifier control circuit has a transmitter and a receiver. The storage circuit is provided in each of the transmitter and the receiver. The storage circuit of the transmitter has a desired output. In addition, the storage circuit of the receiver stores the gain of the AGC amplifier necessary for adjusting the antenna input to a desired level.

Further, the RF attenuator changes in multiple stages, the data conversion circuit stores a plurality of attenuation amounts of the RF attenuator, and the attenuator control circuit determines the amount of attenuation by the RF attenuator when updating the next gain of the AGC amplifier. It is characterized in that a parameter of whether or not it is output is output to a data conversion circuit.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an AGC amplifier control circuit according to the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 show an embodiment of an AGC amplifier control circuit according to the present invention. FIG. 1 is a block diagram illustrating an example of the AGC amplifier control circuit.

<First Embodiment> Transmission Attenuator TX
ATT21, reception attenuator RX ATT10,
This step attenuator has a selective function of allowing the RF signal to pass as it is (OFF state) or attenuating it by a certain amount (ON state). Each of the TX ATT control circuit 29 and the RX ATT control circuit 18
Control is performed so that the attenuation characteristics of the TT21 and the RXATT10 become hysteresis with respect to the transmission or reception level. Further, when the gain of the transmission or reception AGC amplifier is updated next, information indicating whether each of the TX ATT 21 and the RX ATT 10 is in the ON or OFF state is transmitted by T.
The data is output to the X data conversion circuit 28 and the RX data conversion circuit 17.

The transmission AGC amplifier TX AGC 24 and the reception AGC amplifier RX AGC 13 are connected to a transmission or reception IF
Adjust the signal power gain. TX data conversion circuit 28
When the TX ATT 21 is ON and has a certain amount of attenuation, the TX AGC level is generated by adding a level corresponding to the amount of attenuation to the transmission level and performing data conversion.
When the RX ATT 10 has a certain amount of attenuation in the ON state, the RX data conversion circuit 17 performs data conversion by subtracting only the level corresponding to the amount of attenuation from the reception level.
Generate a GC level.

The attenuation data of the TX data conversion circuit 28 and the RX data conversion circuit 17 may be stored in advance,
It is given from an external circuit such as a CPU at the time of initial setting of the circuit. The TX storage circuit 27 and the RX storage circuit 16 store control voltage data of the transmission or reception AGC amplifier corresponding to the transmission or reception level when the transmission or reception attenuator has no attenuation. Transmit or receive digital-to-analog converter TX D / A26, RX D / A
15 converts the control voltage data of the transmission or reception AGC amplifier into an analog voltage and outputs the analog voltage;
The gain of the RX AGC 13 is controlled.

<Description of Operation> Next, the operation of the present invention will be described in detail with reference to the drawings. First, the transmitter will be described. The TX ATT control circuit 29 controls the TX AT
T21 is controlled in a hysteresis manner with respect to the transmission level as shown in FIG. TX ATT21 is OFF
When the transmission level is lower than the point A in the state, TX
The ATT 21 changes to the ON state. When the transmission level becomes higher than the transmission level B from this state, the TX ATT 21 returns to the OF state again.
F, and the RF signal passes through without being attenuated. Also, T
At points A and B at which X ATT 21 switches ON / OFF, the TX AGC 24 sets the gain to TX A so that the transmission level at the antenna end does not change discontinuously.
It must be changed in the opposite direction by the same amount as the attenuation of TT21.

FIG. 2B shows the relationship between the transmission level and the required gain of the TX AGC 24. The unit of the transmission level and the gain of the TX AGC 24 is [dB].
And the control voltage data is generated such that the slope becomes “1”. Therefore, the change in the transmission level is caused by TX AGC2
4 corresponds to one gain change. Also, TX AT
A straight line when T21 is OFF is defined as a TX reference characteristic. When the TX ATT 21 switches from OFF to ON at the transmission level A, the transmission level of the TX reference characteristic becomes T
A desired gain can be obtained by adding the amount by the amount of attenuation of XATT21 and shifting to the right. TX ATT21
While the is ON, a value obtained by adding the attenuation of the TX ATT 21 to the transmission level is set as the TX AGC level.

When the transmission level reaches point B with TX ATT 21 turned on, TX AG
The C level takes a value larger than the point B by the amount of attenuation. When the TX ATT 21 switches from ON to OFF at the transmission level B, a desired gain can be obtained by making the TX reference characteristic equal to the transmission level except for the amount of attenuation previously added from the TX AGC level in the TX reference characteristics. The TX data conversion circuit 28 adds the amount of attenuation to the transmission level when the TXATT 21 is ON, and generates and outputs the TX AGC level with the transmission level as it is when the TXATT 21 is OFF.

In FIG. 2B, when the TX AGC level is used instead of the transmission level, the TX ATT 21
Only by storing the characteristics when
Control when the ATT 21 is ON is also possible. FIG. 2C shows the relationship between the transmission level and the TX AGC level, and the gain of the TX AGC 24. The TX storage circuit 27 stores the transmission control voltage data of the transmission level versus the gain characteristic of the TX AGC 24 when the TX ATT 21 is OFF, and uses the TX AGC level as an address instead of the transmission level. This allows
A desired gain of the TX AGC 24 can be obtained in consideration of the ON / OFF state of the TX ATT 21.

Next, the receiver will be described. RX AT
The T control circuit 18 controls the RX ATT 10 in a hysteretic manner with respect to the reception level as shown in FIG. When the RX ATT 10 is in the OFF state and the reception level becomes higher than the point B, the RX ATT 10 turns on. If the reception level becomes lower than the point A from this state, RX
The ATT 10 is turned off again, and the RF signal passes through without being attenuated. At points A and B at which the RXATT 10 switches between ON and OFF, the gain of the RX AGC 13 must be changed in the opposite direction by the same amount as the attenuation of the RXATT 10 so that the input level of the demodulator DEM 14 does not change discontinuously. .

FIG. 3B shows the relationship between the reception level and the required gain of the RX AGC 13. The unit of the reception level and the gain of the RX AGC 13 is [dB]
And the control voltage data is generated such that the slope becomes “−1”. Therefore, RX A changes with the reception level.
The change in the gain of the GC 13 changes one-to-one in the opposite direction. Further, a straight line when the RX ATT 10 is OFF is defined as the RX reference characteristic. RX A at reception level B
When the TT 10 switches from OFF to ON, a desired gain can be obtained by subtracting the amount of attenuation of the RX ATT 10 from the reception level of the RX reference characteristic and shifting to the left.

While the RX ATT 10 is ON, the value obtained by subtracting the attenuation of the RX ATT 10 from the reception level is represented by R
X AGC level. When the reception level reaches the point A with the RX ATT 10 kept ON, the RX AGC level takes a value smaller than the point A by the amount of attenuation in the RX reference characteristic. When RX ATT10 switches from ON to OFF when the reception level is point A, RX ATT10
A desired gain can be obtained by making the reception level equal to the reception level except for the amount of attenuation subtracted earlier from the AGC level. When the RX ATT 10 is ON, the RX data conversion circuit 17 subtracts the attenuation from the reception level,
If it is OFF, the RX AGC level is generated and output with the received level unchanged.

In FIG. 3B, when the RX AGC level is used instead of the reception level, the RX ATT10
By simply storing the characteristics when
Control when the ATT 10 is ON is also possible. FIG. 3C shows the relationship between the reception level versus the RX AGC level and the gain of the RX AGC 13. The RX storage circuit 16 stores reception control voltage data of the gain characteristic of the RX AGC 13 with respect to the reception level when the RX ATT 10 is OFF, and uses the RX AGC level as an address instead of the reception level. This allows
A desired gain of the RX AGC 13 can be obtained in consideration of the ON / OFF state of the RX ATT 10.

According to the first embodiment of the present invention, the transmission or reception level corresponds to ON / OFF of the attenuator, and data conversion is performed in consideration of the attenuation of the attenuator. For this reason, the data stored in the storage circuit is only the control voltage data when the attenuator is off, so that the data capacity of the storage circuit is small.

The TX AGC level and the RX AGC level obtained by converting the transmission or reception level data include ON / OFF information of the attenuator. For this reason,
There is no need to add ON / OFF information of the attenuator to the address of the storage circuit, and the number of bits does not increase.

<Second Embodiment> Next, a second embodiment of the present invention will be described. In the above-mentioned transmitter / receiver, an attenuator is described using a single-stage step attenuator, but an attenuator that changes stepwise in multiple stages may be used. In this case, the TX data conversion circuit 28 and the RX data conversion circuit 17 store a plurality of attenuation amounts of the attenuator. Next, when the transmission or reception AGC amplifier updates the gain, the TX ATT control circuit 29 and the RX ATT control circuit 18 transmit a parameter indicating how much attenuation the transmission or reception attenuator has to the TX data conversion circuit 28. Alternatively, it outputs to the RX data conversion circuit 17. The TX data conversion circuit 28 and the RX data conversion circuit 17 perform data conversion on the transmission level or the reception level using the attenuation amount corresponding to the given parameter.

The second embodiment of the present invention has an effect that the attenuation of the attenuator can be changed in multiple stages in addition to the effect of the first embodiment.

The above embodiment is an example of a preferred embodiment of the present invention. However, it is not limited to this.
Various modifications can be made without departing from the spirit of the present invention.

[0037]

As is clear from the above description, in the AGC amplifier control circuit of the present invention, the storage circuit stores the gain of the AGC amplifier in association with the desired output, activates the RF attenuator, and sets the predetermined attenuation. If so, the data conversion circuit performs data conversion so as to increase the gain of the AGC amplifier in accordance with the amount of attenuation. Therefore, by using, as the address of the storage circuit, the value after data conversion of the transmission or reception level in consideration of the attenuation of the attenuator, the amount of data stored in the storage circuit can be reduced, and the data amount can be reduced. It is.

Since the data of the same number of bits generated after data conversion of the transmission or reception level contains ON / OFF information of the attenuator, the ON / OF information is included.
There is no need to add data representing F information. As a result, the number of bits of the address does not increase, and the number of pins of the storage circuit can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an AGC amplifier control circuit of the present invention.

FIG. 2 is an explanatory diagram of data conversion of a transmitter according to the present invention.

FIG. 3 is an explanatory diagram of data conversion of a receiver according to the present invention.

FIG. 4 is a block diagram showing a configuration example of a conventional AGC amplifier control circuit.

FIG. 5 is a diagram illustrating an example of a gain characteristic of a conventional AGC amplifier.

FIG. 6 is a diagram illustrating a characteristic example of a conventional transmission control voltage.

FIG. 7 is a diagram illustrating an example of a gain characteristic of a conventional TX AGC.

FIG. 8 is a diagram illustrating a characteristic example of a conventional reception control voltage.

FIG. 9 is a diagram illustrating an example of gain characteristics of a conventional RX AGC.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 antenna 2 duplexer 10 reception attenuator (RX ATT) 11 LNA (Low Noise Amp) 12 down converter 13 reception AGC amplifier (RX AGC) 14 demodulation circuit (DEM) 15 reception digital-to-analog converter (RX D / A) 16 reception storage Circuit 17 Receive data conversion circuit 18 Receive attenuator control circuit 20 Power amplifier 21 Transmission attenuator (TX ATT) 22 Driver amplifier 23 Upconverter 24 Transmission AGC amplifier (TX AGC) 25 Modulation circuit 26 Transmission digital / analog converter (TX D / A) 27 transmission storage circuit 28 transmission data conversion circuit 29 transmission attenuator control circuit 30 reception attenuator control device 40 transmission attenuator control device

Claims (6)

(57) [Claims] An R signal for controlling a gain of an RF signal in a stepwise manner.
An F attenuator (ATT); an AGC amplifier for continuously controlling the gain of the RF signal; a storage circuit for storing data for linearly controlling the gain control of the AGC amplifier; A data conversion circuit for outputting control data for obtaining a gain for compensating a large amount of attenuation by the AGC amplifier to the storage circuit; and receiving a predetermined RF level control signal to control operations of the RF attenuator and the data conversion circuit. And an ATT control circuit, which associates the gain of the AGC amplifier with a desired output.
Serial memory circuit stores the RF attenuator is activated when having a predetermined attenuation amount
Increase the gain of the AGC amplifier in accordance with the amount of attenuation.
For ease of data conversion, the data conversion circuit performs data conversion.
The reception level to the address of the storage circuit.
Use the value after data conversion considering the attenuation of the tenator
Thus, the amount of data stored in the storage circuit can be reduced, and
An AGC amplifier control circuit characterized in that the data amount can be reduced . 2. The AGC amplifier control circuit according to claim 1, wherein the AGC amplifier control circuit includes a transmitter and a receiver. 3. The storage circuit is provided in each of the transmitter and the receiver, wherein the storage circuit of the transmitter is for a desired output, and the storage circuit of the receiver is for setting an antenna input to a desired level. 3. The AGC amplifier control circuit according to claim 2, wherein gains of the AGC amplifier required for adjustment are stored. 4. The AGC amplifier control circuit according to claim 1, wherein the RF attenuator changes in multiple stages. 5. The AGC amplifier control circuit according to claim 4, wherein said data conversion circuit stores a plurality of attenuation amounts of said RF attenuator. 6. The attenuator control circuit according to claim 6, wherein:
6. The AGC amplifier control circuit according to claim 4, wherein a parameter indicating the amount of attenuation of the RF attenuator is output to the data conversion circuit when the gain of the C amplifier is updated next.